It was supposed to be a glorious return to the Football League, after two and a half years in non-league.
Sinnott was hoping to play a full part in Chesterfield’s promotion push, having signed a two-year deal under Gary Caldwell’s management regime.
But as the end of the League Two season draws near, Sinnott has just four starts to his name.
Despite scoring twice in his first four appearances back in August, he fell out of favour with Caldwell and struggled to see first team action.
Jack Lester replaced Caldwell at the end of September and Sinnott was on the verge of breaking into the team thanks to some impressive performances in training.
It wasn’t to be for the former Huddersfield Town man however, a pair of ruptured ligaments in his ankle sidelining him for four months.
“It has been frustrating, with the league position we’re in and picking up this injury, being out for coming up to four months now,” he said.
“At the time, the lads who were in were doing well, but I got a bit of feedback from the coaches and they were happy with my attitude in training, telling me to keep biding my time.
“It was the day before the Mansfield game, which was very frustrating, but when I did it I didn’t think it was going to be as bad as it was.
“That’s football, it doesn’t always go as you plan it.”
It’s been a long road back for the 24-year-old, but it’s not the first time he’s faced a lengthy spell in the treatment room.
“I dislocated my kneecap at Huddersfield when I was 19 and that’s helped me a bit, to be fair,” he said.
“When I got that injury I struggled a bit, it was my first long-term injury, but it stood me in good stead to get my head down this time and get back into training as soon as I could.”
All’s well that ends well and Sinnott is now back in full training and itching to return to the Proact pitch.
He’s building up his fitness in order to make that possible.
“The ankle is fine, it has been for about two or three weeks.
“I’m really happy to get back in training, just trying to get back up to speed at the moment.
“I think we’ll have an 11 v 11 in training this week, it will be good to get some minutes in a match-type scenario.”
Of course it’s not simply a case of declaring yourself fit and being handed a shirt – fellow attack-minded midfielders Louis Dodds, Josh Kay, Joe Rowley and Andy Kellett are all vying for a starting place.
Sinnott’s aim is to train the way he did when he caught Lester’s eye, just prior to damaging his ankle.
“I’ll just work in training, do extra bits where I can, to try and get me back up to that level I was at before I got injured,” he said.
“Competition is not really a bad thing, is it? We bring the best out of each other on the training field.
“If you get the shirt on a Saturday or Tuesday night, you’ve got players capable of fighting for it in training.
“I’ve always had faith in my own ability that I could affect games.”
Finishing just above the relegation places might fall someway short of the fairytale debut season Sinnott had in mind when he joined the club, but all things considered it would be a high note to end upon.
“We’ve just got to dig in now for the last games of the season and hopefully we’ll stay up.
“We have 10 games left, 30 points to play for.
“It does help that we play games against those sides in and around us, and we have games in hand over one or two.
“It’s still in our hands.
“We’ve got to dig deep, be ready for the fight and make sure we go and get those points.”